Honestly I think even if she doesn't suspect he's cheating, he seems to treat her like a sex object and I wouldn't be surprised if she's sick of being groped and winked at by a man who hasn't even noticed she likely has PPD. I also have a ton of questions about how involved he is in parenting. It can be hard enough to get your mojo back in the first couple years after a baby, but even less so if your husband is being a useless sex pest, I would imagine.